Thunderbird - technical definition

(1) A full-featured e-mail client for Windows, Mac and Linux from the Mozilla Foundation. It provides unique features including a Saved Search feature that provides a virtual mailbox based on specific search criteria. For example, all mail from a particular person can be in a Saved Search folder although the physical messages are stored in several other mailboxes.

Like its Firefox Web browser counterpart, Thunderbird also supports "extensions," which are plug-ins that enhance the program. For more information, visit www.mozilla.org. See Firefox and Penelope.

(2) The code name for AMD's 1.1 GHz Athlon processor introduced in August 2000. The L2 die is on cache. See AMD.